Study of microbial spread when using multiple-use nasal anaesthetic spray

Background: Current economic constraints have led to the emergence of reusable anaesthetic sprays with replacement nozzles (Xylocaine) as an alternative to disposable anaesthetic solutions (Co-phenylcaine) for rhinological procedures. The former costs 213.84 per year vers12,047.69 for the latter, at equivocal doses. However, research regarding the sterility of such instruments is limited. The aim of this in vitro study was to determine whether bottles of Xylocaine could pose a risk of cross-infection to patients. Methods: Two techniques were used. The first was to introduce nozzles into methylene blue and fluorescein dyes, and then analysing the anaesthetic solutions using spectrophotometry for assessment of colour change indicating retrograde contamination. The second method involved spraying Xylocaine into cultures of Staphylococcus aureus with concurrent nozzle changes. This was repeated over a 36-day-period. Sterility checks were performed on the Xylocaine before and after inoculation into the culture. Results: None of the anaesthetic solutions showed the presence of dyed saline following spectrophotometric analysis. No S. aureus was isolated from any of the 30 spray bottles cultures over the 36-day trial period. Conclusion: It was demonstrated that using the Xylocaine spray with disposable nozzles for each patient should not pose a cross infection risk to patients.